Sputtering Target Microcracks for High Power Density

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Solution Overview

Problem

Sputtering targets made of brittle materials face challenges with high sputtering power densities due to thermal and mechanical stress, leading to fracture and limited complex geometry production, as they have low plastic deformation capacity and poor thermal shock resistance.

Innovation Solution

A sputtering target with a ceramic target plate and a molybdenum back plate connected via a high-temperature solder with a melting point above 400°C, creating microcracks that reduce mechanical tensile stress and enhance thermal conductivity, allowing for high power density sputtering without failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high sputtering power density is applied to brittle material targets, then sputtering productivity is improved, but thermal and mechanical stress causes target fracture

Engineering Contradiction:
Improvesputtering productivityVSAvoidtarget fracture resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The target plate is divided into multiple segments through controlled microcracks that extend from the front to the back surface. These microcracks partition the brittle material into adjacent fragments, allowing each segment to independently accommodate thermal expansion and stress without causing complete target failure. This segmentation enables the target to withstand high sputtering power densities while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

2Strength

If brittle material is used for sputtering target, then material performance is improved, but mechanical deformation capacity deteriorates

Engineering Contradiction:
Improvematerial performanceVSAvoidmachinability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

Complex geometries such as cooling channels, holes, and bayonets are manufactured in the back plate before the brittle target material is applied. This preliminary fabrication of complex features in the ductile back plate material avoids the need to machine the brittle target material directly, thereby preserving both the high performance of the brittle sputtering material and the ability to create complicated geometries.

Inventive Principle:
Principle #10Preliminary action

3Strength

If back plate is added to brittle target, then mechanical strength is improved, but device complexity increases

Engineering Contradiction:
Improvemechanical strengthVSAvoidtarget structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The back plate and target plate are merged into a single integrated component through a bonding process. The back plate, made of ductile material with complex geometries, is bonded to the brittle target material, creating a composite structure that combines the mechanical strength and geometric flexibility of the back plate with the sputtering performance of the target material. This merging approach simplifies the overall device by integrating multiple functions into one component.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables sputtering targets to operate at high power densities without breaking and facilitates the production of complex geometries, ensuring mechanical and thermal stability, thus extending the target's lifespan and enabling higher sputtering power usage.

Implementation Method 1

a back plate via a bonding solder that has a melting point of greater than 400 °C

Methodology Applied
Scientific EffectSoldering: Soldering

Implementation Method 2

the target plate has microcracks which go through from the front to the back and divides the target plate into adjacent fragments

Methodology Applied
Scientific EffectStress distribution through microcracks: Fracture Mechanics

Implementation Method 3

enhance thermal conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3161180B1Sputtering target
Publication Date: 2019.02.06 PLANSEE COMPOSITE MATERIALS
  • EP3161180B1 patent drawingFigure 1~2
  • EP3161180B1 patent drawingFigure 3~4

AI summary

The invention relates to a target, in particular a sputtering target, which comprises a target plate of a brittle material and a backplate, wherein the backplate is connected to the target plate over its surface area and the target plate has microcracks, which pass through from the front side to the rear side of the target plate and divide the target plate into adjacent fragments. Similarly, the invention relates to a method for producing such a target. A target according to the invention is suitable in particular for the use of extremely high power densities. The invention likewise relates to a vacuum coating method, in which at least one target according to the invention is used as a sputtering target, and as a result particularly high power densities can be used on the target during the sputtering.